I dont believe your symtoms are due to multiple tvs.
I believe it is a pip issue.
We have only one tv connected to H3 (hdmi) and have had the frozen/flashing issue during pip.
Sometimes on only one of the multiple selected feeds (tuners),
and sometimes on multiple of the quad-pip feeds (tuners).
More recently we are having audio dropouts on pip.
The audio dropouts seem to start when 10-back or timeshift is used, and the dropouts continue even when back to live.
Rather than reset H3, we found channel up/down and back resets that particular feed (tuner) and the issues is resolved.
Sent from my SM-G930P using the
SatelliteGuys app!